Grow Mediums Promix HP Myco seems too wet

[NorthernBoreal]

I am a first time grower. I have my autos planted in promix hp myco and the medium never seems to dry out.
Here is my setup:

5 gallon home depot buckets with 1/2" holes drilled every 2 inches on the sides and about a dozen 3/4" holes in the bottom

1000 watt led bulb running 24 hours a day
temp is a constant 25 degrees celcius
I have good airflow into my grow box (2'x3'x5' lined with mylar) you can feel the air being sucked in the bottom hole hard and I have a fan blowing on the plants

The plants are 15 days old after germination and they seem really healthy, dark green leaves with thick stems that are short with dense leaf growth.

They recieved 1/2 liter of water each in the first 10 days
and I have only fed them 2 times 1l on day 10 and 1l on day 13

I am super paranoid about over watering as the medium is damp all the way to the bottom. Should I worry or should I continue to feed them every 3 days like I have been?

 

[Flash Growdon]

I use this medium but with fabric pots now.but I used plastic pails before them actually lol With small plants that don't drink much and a long bucket like that the roots will be able to search Deep for water so I'd say lift bucket now feel the weight do not water until that pail is fairly light then I'd only water until a lil water comes out or you can feel through the whole at bottom plants can do better dry for few days then too wet just from my experience good luck

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